The Biodiversity Gradient Experiment is a long-term study to examine the impact of plant diversity on the delivery of ecosystem services from annual cropping systems. It consists of 21 different experimental treatments that range from bare soil to continuous corn, soybean or wheat—without or with a cover crop, to mixed rotations of these crops—without or with cover crops(s), to annually fallowed fields with early successional plant communities. Species richness of these treatments ranges from 0, 1, 2, 3, 4, 5 to >15 in a 3-year rotation cycle.
The experiment was established in 2000 at the LTER Main Site. Treatment plots are 9 x 27 m and replicated in each of 4 randomized blocks. See the plot map for treatment codes and descriptions. Management is based on the Biologically Based treatment of the Main Cropping System Experiment. Lysimeters (soil water samplers) are installed in 24 plots.